You can find out how to easily share a WiFi password with the iPhone here..
Since iOS 11, you can easily share WiFi passwords between Apple devices. This works between iPhone, iPad and Mac. In these instructions you will find out what requirements there are for this and how exactly sharing works.
Before you can share passwords, there are a few things you need to make sure of:
Follow our step-by-step instructions or take a look at the quick start guide .